My horses are disappearing and things keep getting destroyed when I'm not in

So I created a new world and my friends joined. We had a really fun time but then I had to leave the game. While I was my friend texted me and it said "[Insert Name] it's says your still in the game." I wasn't in the game. Weird... When we joined back in some of our stuff was missing! When the creator leaves the game all the other people get disconnected.

So can you please help us? Thanks!